As illustrated in FIG. 10, a steering apparatus for an automobile is constructed so as to transmit the movement of a steering wheel 1 by way of an steering shaft 2 and an intermediate shaft 3 to a steering gear unit 4 that steers the wheels. The steering shaft 2 and an input shaft 5 of the steering gear unit 4 normally cannot be arranged on the same straight line. Therefore, an intermediate shaft 3 is provided between the steering shaft 2 and the input shaft 5, and both end sections of the intermediate shaft 3 and end sections of the steering shaft 2 and input shaft 5 are joined by way of a cross shaft universal joint 6 that is called a Cardan joint. With this kind of construction, it becomes possible to transmit rotation between the steering shaft 2 and input shaft 5 that are not on the same straight line.
FIG. 11 and FIG. 12 illustrate an example of a conventional cross shaft universal joint as disclosed in JPH10205547 (A). The cross shaft universal joint 6 includes a pair of yokes 7a, 7b that are made of metal plate, and a cross shaft 8. Of the pair of yokes 7a, 7b, one yoke 7a (right yoke in FIG. 11 and FIG. 12) includes a base section 9a, and a pair of joining-arm sections 10 that extend from the edge of one end (edge on the left end in FIG. 11 and FIG. 12) in the axial direction of the base section 9a. 
The base section 9a is formed into an incomplete cylindrical shape that is not continuous at one location in the circumferential direction, and the inner diameter of the base section 9a is able to expand or contract in order that the end section of a rotating shaft (not illustrated in the figure) such as a steering shaft can be inserted. Moreover, a pair of flanges 11a, 11b that face each other are provided on the base section 9a so as to sandwich the non-continuous section from both sides in the circumferential direction. A through hole 12 for inserting the rod section of a bolt (not illustrated in the figures) is formed in one of the flanges 11a (lower flange in FIG. 12) of the pair of flanges 11a, 11b. On the other hand, a through hole 13 is formed in the other flange 11b (upper flange in FIG. 12) of the pair of flanges 11a, 11b, and a nut 14 is press-fitted and fastened in the through hole 13, and that nut 14 functions as a screw hole for screwing the bolt into the other flange 11b. 
The pair of joining-arm sections 10 extend in the axial direction of the base section 9a from two locations on opposite sides in the radial direction of one end section in the axial direction of the base section 9a, and are such that the inside surfaces face each other. Circular holes 15 that are coaxial with each other are formed in the tip end sections of the pair of joining-arm sections 10.
The other yoke 7b (left yoke in FIG. 11 and FIG. 12) of the pair of yokes 7a, 7b is such that only the shape of the base section 9b differs from the one yoke 7a. The base section 9b of the other yoke 7b is a complete cylindrical shape in order to insert an end section of a rotating shaft 16 such as the intermediate shaft.
The cross shaft 8 is constructed by two shaft sections 17a, 17b that are provided so as to intersect in a cross shape, and of these shaft sections 17a, 17b, both ends of one of the shaft sections 17a are pivotally supported on the inside of a pair of circular holes 15 that are formed in the pair of joining-arm sections 10 of the one yoke 7a, and both end sections of the other shaft section 17b are pivotally supported on the inside of a pair of circular holes 15 that are formed in the pair of joining-arm sections 10 of the other yoke 7b. More specifically, the tip end sections of each of the shaft sections 17a, 17b of the cross shaft 8 are supported on the inside of the circular holes 15 by way of cup bearings 18 so as to rotate freely.
Each of the cup bearings 18 corresponds to a shell type needle bearing and includes one cup 19 that corresponds to a shell type outer ring, and plural needles 20. The cup 19 is formed by processing hard metal plate such as carbon steel plate and case hardened steel plate using plastic working such as deep drawing, and includes a cylindrical section 21, a bottom section 22 and an inward facing flange section 23. The bottom section 22 entirely covers the side of one end in the axial direction of the cylindrical section 21 (outside surface side of the joining-arm section 10 when assembled in a circular hole 15). The inward facing flange section 23 bends and extends inward in the radial direction from the other end section in the axial direction of the cylindrical section 21 (end section of the inside surface side when assembled in the circular hole 15), and the surface that faces the needles 20 is curved in a direction to form a concave surface. Each of the cups 19 is such that when press-fitted inside the circular hole 15, crimped sections 24 are formed by plastically deforming plural locations in the circumferential direction of the edge section of the opening of the circular hole 15 of the outside surface of the joining-arm section 10 inward in the radial direction. With this kind of construction, the cup 19 is prevented from coming out in the outward direction from the circular hole 15. The tip end sections of the shaft sections 17a, 17b of the cross shaft 8 are each inserted into the inside in the radial direction of the needles 20.
When joining the end sections of the two rotating shafts 16, 25 by way of the universal joint 6 that is constructed in this way, first, the end section of the rotating shaft 16 is tightly inserted or press-fitted inside the base section 9b of the other yoke 7b of the pre-assembled universal joint 6, and in this state the base section 9b and the end section of the rotating shaft 16 are welded and fastened together. Next, the end section of another rotating shaft 25 is fitted inside the base section 9a of the one yoke 7a of the universal joint 6 with a spline fit, and in this state, the tip end section of a bolt (not illustrated in the figures), the rod section of which has been inserted through the through hole 12 that is formed in the one flange 11a, is screwed into the nut 14 that was fastened to the other flange 11b and tightened. As a result, by causing the base section 9a to contract by reducing the space between the pair of flanges 11a, 11b, the end section of the other rotating shaft 25 is joined and fastened to the base section 9a. 
The universal joint 6 is assembled by joining the pair of yokes 7a, 7b by way of the cross shaft 8. FIG. 13A and FIG. 13B illustrate an example of a conventional method for assembling the universal joint 6. When doing this, a yoke clamping jig 26 is used for supporting the pair of yokes 7a, 7b. The yoke clamping jig 26 includes a pair of L-shaped supporting-arm sections 27 and a motor (not illustrated in the figures) for moving the supporting-arm sections 27. In order to attach the shaft sections 17a, 17b of the cross shaft 8 to the pair of yokes 7a, 7b, press-fitting punches 28 and crimping punches 29 are used. The press-fitting punches 28 are formed into a circular column shape, and are able to move in the forward-backward direction (left-right direction in FIG. 13A and FIG. 13B) by press-fitting cylinders (not illustrated in the figures) that are provided on the base-end sides. On the other hand, the crimping punches 29 are formed into a cylindrical shape, and fit around the press-fitting punches 28. The crimping punches 29 are able to move in the forward-backward direction (left-right direction in FIG. 13A and FIG. 13B) by crimping cylinders (not illustrated in the figures) that are provided on the base-end sides.
When assembling the universal joint 6, first, both end sections of the one shaft section 17a of the cross shaft 8 are gently inserted inside the pair of circular holes 15 of the one yoke 7a, and in this state, the tip-end sections of the pair of supporting-arm sections 27 of the yoke clamping jig 26 are arranged inside the pair of joining-arm sections 10. Moreover, the press-fitting punches 28 and crimping punches 29 are arranged in positions on both sides sandwiching the pair of joining-arm sections 10 so that each is coaxial with the center axis of the circular holes 15. Next, by driving the motor of the yoke clamping jig 26, the pair of supporting-arm sections 27 are synchronously moved in directions going away from each other in the direction of the center axis of the circular holes 15. Then, the outside surfaces of the tip-end sections of the pair of supporting arm sections 27 are brought in contact with the inside surfaces of the tip end sections of the pair of joining-arm sections 10, and support the pair of joining-arm sections 10.
Furthermore, by moving each press-fitting punch 28 in the forward direction (direction toward the yoke 7a), the inside surfaces of the bottom sections 22 of the cups 19 of the cup bearings 18 are pressed against the tip-end surfaces of the shaft section 17a, and at the instant that the pressure applied to the press-fitting punches 28 reaches a specified size, or at the instant that the amount that the press-fitting punches 28 have moved in the forward direction has reached a specified amount, movement in the forward direction stops. Next, the crimping punches 29 are moved in the forward direction, plastically deform plural locations in the circumferential direction of the edge sections of the openings of the circular holes 15 of the outside surface of the joining-arm sections 10, and form crimped sections 24 in those portions. As a result, the cup bearings 18 are attached to portions between the circular holes 15 and both end sections of the shaft section 17a, and both end sections of the shaft section 17a are supported on the inside of the circular holes 15 by way of the cup bearings 18. Attaching the other yoke 7b and the shaft section 17b of the cross shaft 8 is performed in the same way.